The present invention relates to a remote platform multiple capture image formation method and apparatus and, more particularly, but not exclusively to such a system wherein the remote platforms are orbital satellites.
Imaging of the earth's surface from high flying aircraft or from orbital satellites is routinely carried out and is useful for obtaining information for numerous monitoring applications, both civil and military. As the satellite imaging data gets more and more detailed it contains more information and thus allows more and more uses. It is therefore a widely recognized aim to obtain higher resolutions and find processing methods in order to obtain more data from the resolutions available.
One way of increasing the amount of data is to take two images of the same target from different angles. The two images can then be combined into a single stereo image containing height information. In order to obtain the two images from which to form the stereo combination it is usual to have two different cameras spaced apart by a certain difference, and angled to view the same scene. The use of stereo imaging is quite common in satellite photography for application in which surface topography is of importance.
Another way of increasing the amount of data from the imaging process involves mounting on the satellite imaging platform two cameras, one camera being a high-resolution black and white camera and the second camera being a lower resolution color camera. The black and white camera obtains a high-resolution pixel scan, to which color is added from the color camera. A disadvantage of the method is that the two cameras are different cameras producing different images at different resolutions and thus there is not a one-to-one correspondence to allow colors to be applied to the high-resolution pixels.
The use of two cameras is in any case a disadvantage because of increased cost and complexity, and an orbital satellite is not an environment where it is easy to organize repairs. It is therefore desirable to find a method of increasing the data available but using only a single camera.
Satellites are further able to take multiple images of the same target in successive passes. Again the images can be combined. However the time interval between the two passes makes it highly likely that there are significant changes between the two images, in lighting, in cloud cover, in the exact positions from which the two images are taken etc. so that combining the images is not a trivial task.
There is thus a widely recognized need for, and it would be highly advantageous to have, a vehicle inspection system devoid of the above limitations.